Thermal storage arrangements (whether heated by exposure to microwave energy or otherwise) have been widely used for a variety of purposes. Those which are activated by microwave energy have been used for various heating applications. One such arrangement, U.S. Pat. No. 5,211,949 to Salyer, utilizes as a thermal storage material a silica powder with a phase-change material. The material is claimed to be a free-flowing powder when the particle size is between 0.007 and 0.07 microns in diameter above and below the melting temperature of the phase-change material.
Other arrangements where materials have been combined with a powder include U.S. Pat. No. 4,008,170 to Allen, where silica powder has been combined with up to 9 parts by weight water. The water/silica powder is used for cooling or as a source of water.
In U.S. Pat. No. 4,253,983, Blanie discloses paraffin compositions having improved heat reservoir properties. The disclosed paraffin compositions include paraffin combined with two different fillers so as to improve thermal conductivity and plasticity.
The present invention provides for a simple system for providing stored heat that has improved safety and handleability.